1. Field of the Invention
The present invention relates to a method of forming an insulating film, a method of manufacturing a semiconductor device, and a semiconductor device. For example, the present invention relates to an intergate insulating film between floating and control gate electrodes.
2. Description of the Related Art
There has been a semiconductor device having a floating gate electrode, intergate insulating film and control gate electrode, which are successively stacked. In such a semiconductor device, the intergate insulating film is formed of a high-k dielectric film. The high-k dielectric film is used, and thereby, it is possible to suppress a leakage current between the floating and control gate electrodes. In this case, the less the concentration of C contained in the high-k dielectric film used as the intergate insulating film, the greater the leakage current is suppressed.
In the process of manufacturing the semiconductor device, formation of the film is carried out by the deposition using atomic layer deposition (ALD). ALD is a technique of successively depositing each layer at a unit of atomic layer to form a film having a desired thickness. The thickness of the film can be precisely controlled using ALD.
If the high-k dielectric film as the intergate insulating film is deposited using ALD, source gas containing metal element and source gas as oxidant are alternately supplied. Preferably, oxidant having strong oxidation force (strong oxidant) is used in order to suppress C concentration of the high-k dielectric film formed using ALD. JPN. PAT. APPLN. KOKAI Publication No. 2001-152339 and U.S. Pat. No. 6,576,053 disclose a technique of using O3 as the strong oxidant.